Standards have been adopted to provide power to a mobile powered device (PD) through a Universal Serial Bus (USB) cable. The PD typically includes a rechargeable battery, and the power supply typically charges the battery in addition to providing power to operate the device. The power supply is often known as a charging device. A standard for providing power to a PD is the USB Battery Charging Specification 1.2 that defines signals and protocols that allow the charging device and the PD to communicate for the purpose of differentiating between a Standard Downstream Port (SDP), a Charging Downstream Port (CDP) or a Dedicated Charging Port (DCP). In some applications it may be desirable for the PD to obtain additional information from the charging device that may not be addressed in the charging specification, while maintaining compliance with the specification.
Corresponding reference characters indicate corresponding components throughout the several views of the drawings. Skilled artisans will appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to help to improve understanding of various embodiments of the present invention. Also, common but well-understood elements that are useful or necessary in a commercially feasible embodiment are often not depicted in order to facilitate a less obstructed view of these various embodiments of the present invention.